• Journal of applied mathematics & informatics
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• v.5 no.1
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• pp.141-152
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• 1998

Based on the geometric representation an efficient al-gorithm is designed to find all articulation points of a permutation graph. The proposed algorithm takes only O(n log n) time and O(n) space where n represents the number of vertices. The proposed se-quential algorithm can easily be implemented in parallel which takes O(log n) time and O(n) processors on an EREW PRAM. These are the first known algorithms for the problem on this class of graph.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.2
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• pp.9-16
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• 2004

Recently, lattice conditional independence models(LCIMs) have been introduced for the analysis of non-monotone missing data patterns and of non-nested dependent regression models. This approach has been successfully applied to solve various problems in data pattern analysis, however, it suffers from computational burden to search LCIMs. In order to cope with this drawback, we propose a new scheme for finding LCIMs based on the essential graph. Also, we show that the class of LCIMs coincides with the class of all transitive acyclic directed graph(TADG) models which are Markov equivalent to a specific acyclic directed graph(ADG) models.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.27 no.4
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• pp.324-341
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• 2023

Topological data analysis (TDA) is a data analysis technique, recently developed, that investigates the overall shape of a given dataset. The mapper algorithm is a TDA method that considers the connectivity of the given data and converts the data into a mapper graph. Compared to persistent homology, another popular TDA tool, that mainly focuses on the homological structure of the given data, the mapper algorithm is more of a visualization method that represents the given data as a graph in a lower dimension. As it visualizes the overall data connectivity, it could be used as a prediction method that visualizes the new input points on the mapper graph. The existing mapper packages such as Giotto-TDA, Gudhi and Kepler Mapper provide the descriptive mapper algorithm, that is, the final output of those packages is mainly the mapper graph. In this paper, we develop a simple predictive algorithm. That is, the proposed algorithm identifies the node information within the established mapper graph associated with the new emerging data point. By checking the feature of the detected nodes, such as the anomality of the identified nodes, we can determine the feature of the new input data point. As an example, we employ the fraud credit card transaction data and provide an example that shows how the developed algorithm can be used as a node prediction method.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.113-116
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• 2021

As artificial intelligence technologies, including deep learning, develop, these technologies are being introduced to code similarity analysis. In the traditional analysis method of calculating the graph edit distance (GED) after converting the source code into a control flow graph (CFG), there are studies that calculate the GED through a trained graph neural network (GNN) with the converted CFG, Methods for analyzing code similarity through CNN by imaging CFG are also being studied. In this paper, to determine which approach will be effective and efficient in researching code similarity analysis methods using artificial intelligence in the future, code similarity is measured through funcGNN, which measures code similarity using GNN, and Siamese Network, which is an image similarity analysis model. The accuracy was compared and analyzed. As a result of the analysis, the error rate (0.0458) of the Siamese network was bigger than that of the funcGNN (0.0362).

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.265-271
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• 1997

A bond graph modeling approach which is equivalent to a finite element method is formulated in the case of the piezoelectric thickness vibrator. This formulation suggests a new definition of the generalized displacements for a continuous system as well as the piezoelectric thickness vibrator. The newly defined coordinates are illustrated to be easily interpreted physically and easily used in analysis of the system performance. Compared to the Mason equivalent circuit model, the bond graph model offers the primary advantage of physical realizability. Compared to circuit models based on standard discrete electrical elements, the main advantage of the bond graph model is a greater physical accuracy because of the use of multiport energic elements. While results are presented here for the thickness vibrator, the modeling method presented is general in scope and can be applied to arbitrary physical systems.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.422-440
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• 2005

There are many kinds of research on web graph, most of them are focus on the hyperlinked structure of the web graph. Well known results on the web graph are rich-get-richer phenomenon, small-world phenomenon, scale-free network, etc. In this paper, we define a new directed web graph, so called the Web Usage Pattern Graph (WUPG), that nodes represent web sites and arcs between nodes represent a movement between two sites by users' browsing behavior. The data to constructing the WUPG, approximately 56,000 records, are gathered in the Kyungsung University. The results analysing the data summarized as follows: (i) extremely rich-get-richer phenomenon (ii) average path length between sites is significantly less than the previous one (iii) less external hyperlinks, more internal hyperlinks

• 한국해양학회지
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• v.28 no.1
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• pp.72-78
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• 1993

Sediment grain size was analysed and compared for standard solids and sediment samples using two different methods; SediGraph and MasterSizer. SediGraph results on sediment samples appeared as finer than those of MasterSizer, and the difference is great especially for biogenic siliceous ooze. The difference is maybe due to the following different points in two methods; pretreatment procedure, sample concentration, detachability on fine grains (about 1 um), and detection principle on nonspherical grains.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.2
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• pp.19-23
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• 1984

A new directed product graph(DPG) is proposed from the product graph for electrical networks. By introducing the direction of an dege and the concept of a loop to product graph, it is more easy and rapid to obtain topologically the denominator of Mason's formula without relation of the sign rule and without arising terms cancelled. Also the constraints of tree selection at a given network-graph can be removed.

• International Journal of Computer Science & Network Security
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• v.22 no.1
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• pp.121-128
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• 2022

There are much processing techniques of microwave circuits, whose dimensions are small compared to the wavelength, but the disadvantage is that they cannot be directly applied to circuits working at high and/or low frequencies. In this article, we will consider the bond graph approach as a tool for analyzing and understanding the behavior of microwave circuits, and to show how basic circuit and network concepts can be extended to handle many microwaves analysis and design problems of practical interest. This behavior revealed in the scattering matrix filter, and which will be operated from its reduced bond graph model. So, we propose in this paper, a new application of bond graph approach jointly with the scattering bond graph for a high frequency study.

• Korean Institute of Interior Design Journal
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• v.23 no.2
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• pp.166-173
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• 2014

This study analyzed visual-perceptual centrality as a measure to solve the confusion that might occur in visitor's movement in analyzing contemporary museums that have recently expand. Also, this study proposed a new methodology to understand the relationships of the occurrence and convergence of visual-perceptual power. The existing visibility graph analysis mostly ends up in identifying nodes corresponding to the physical environment of museums while the newly proposed visibility graph analysis is a methodology that can analyze the landmark on which the visual-perceptual power occurs and converges, by setting visible space elements as analysis variables, which showed a possibility to draw more reliable results in parallel to the existing analysis, and the results of this analysis are as follows. A public museum located in downtown has a limitation that it cannot but be multi-layered as a way to enlarge for the accommodation of a variety of programs on a limited site. Also, this study found that the problem of visitor orientation occurring in the multi-layer process was solved by a major space which was visual-perceptually void. Also, its types can be summarized into two types: One is setting parameter spaces (ramps, staircases, hallways) linked visual-perceptually to the major space and the other is solving the confusion of the visitor's movement by composing a simple exhibition space. In particular, it is judged that the type solving the confusion of the visitor's movement by composing a simple exhibition space also had a relationship with changes in the characteristics of the exhibited works by period. In addition, it was found that the entrance also appeared in two types: dependent type and independent type in the major space according to the characteristics of the major space.